It is often desirable to deliver inoculations, medications, or other injectable substances to a large number of recipients. For example, it has been shown that vaccinations are an effective method for reducing and/or eliminating the spread of communicable diseases. However, the delivery of injections to large numbers of people presents several problems including expense, difficulty of transportation, cross-contamination between recipients, and the creation of hazardous biowaste. These problems can be compounded in economically deprived areas where resources may be limited.
Current methods for delivering vaccinations to populations of recipients typically use needled syringes. These methods typically require filling of the syringes and disposal of the needle and syringe after each use. Even in the hands of the most careful users, accidental needle sticks, and the accompanying concerns about cross-contamination take place.
Needle-free injection systems allow a faster immunization process than needled syringes and eliminate the possibility of accidental needle sticks. However, because the nozzle of the needle-free injector (rather than a disposable needle) makes contact with the patient during injection, the use of current needle-free injection systems to inject multiple patients raise concerns about contamination unless the equipment is properly sterilized between injections. Therefore, it is important that equipment is properly sterilized between injections. However, this can increase costs and reduce the number of injections that can be administered in a given time period, decreasing the likelihood that everyone who needs or wants a vaccination will receive one.